The invention relates to transmissions and, more particularly, to overdrive transmissions for marine propulsion devices and the like.
With increasing horsepower of marine propulsions devices, such as outboard motors and stern drive units, the use of an overdrive unit becomes more desirable to improve fuel economy, engine life, lower unit life, and overall performance. A lower pitch propeller can be used for acceleration and, after the boat is planing, an overdrive can be activated to permit the engine speed to be lowered without decreasing the propeller speed. Higher drive shaft speeds made possible when operating in the overdrive mode result in lower torque loading between the drive gear on the drive shaft and the pinion gears on the propeller shaft with an increase in the life of the lower unit and fuel economy.
Examples of other constructions of multi-speed transmissions are disclosed in the following United States patents:
______________________________________ U.S. Pat. U.S. Pat. No. ISSUE DATE ______________________________________ Molly 1,795,135 March 3, 1931 Pilaar 1,979,077 Oct. 30, 1934 Kohr 2,466,318 April 5, 1949 Kreidler 2,861,461 Nov. 25, 1958 Halberg et al. 3,129,602 April 21, 1964 Orcutt et al. 3,372,601 March 12, 1968 Avramidis et al. 3,884,097 May 20, 1975 Strang 4,173,939 Nov. 13, 1979 ______________________________________